craniometry (craniology)

Craniometry is the measurement of cranial features in order to classify people
according to race, criminal temperament, intelligence, etc. The underlying
assumption of craniometry is that skull size and shape determine brain size
which determines such things as intelligence and capacity for moral
behavior. Empirical evidence for this assumption is not very strong. This
fact has not hindered small-headed people from claiming they are members of
a superior race or gender because the head size of their racial or gender
group is larger on average than the head size of some other racial or gender
group. As members of superior races and gender, these small-headed people
reason that they, too, must be superior to all members of races inferior to
their own and of all members of the other gender. In logic, this is called
the fallacy of division: reasoning that what is true of the whole or group
must also be true of the parts or members of the group.

In the 19th century, the British used craniometry to justify its racist policies toward
the Irish and black Africans, whom the British considered to be inferior races. Irish
skulls were said to have the shape of Cro-Magnon men and were akin to that of apes, proof
of their inferiority along with black Africans. In France, Paul
Broca demonstrated that women are inferior to men because of their
smaller crania. He argued against higher education for women because their
small brains couldn't handle the demands.*

In the 20th century, the Nazis used craniometry and anthropometry
to distinguish Aryans from non-Aryans. The Belgians used these
pseudosciences, among other things, to distinguish Hutus from Tutsis in
Rwanda. "In the 1930s the Belgians required everybody [in Rwanda] to start
carrying an identity card classifying themselves as Hutu or Tutsi, thereby
markedly increasing the ethnic distinction that had already existed"
(Diamond 2005: 314).

"Forensic anthropologists believe that by taking some 90 measurements of
a skull they can correctly assign its owner's continent of origin - broadly
speaking, its race, though many anthropologists prefer not to use that term
- with 80 percent accuracy" (Wade 2002).

The first craniometer was invented by Augustus Pitt Rivers (1827-1900), an archaelogist. He invented the device to make exact measurements of human skulls.